The purpose of this investigation was to determine the comparability of flexible endoscopy to rigid endoscopy in the examination of rabbit vocal folds in vivo. This work was conducted within a larger parent project that has investigated the adverse effects of combination inhaled corticosteroids (ICs) on voice function in animal models and humans. In this study, both flexible and rigid vocal fold imaging was performed on eight rabbits; four having received ICs and four that were from control conditions. Original recordings were examined frame-by-frame to identify similar views, zoomed in and zoomed out, for flexible and rigid samples. Images were extracted, cropped, and placed in a slide presentation for purposes of visual-perceptual ratings. Two board-certified laryngologists from the parent project performed ratings that included the following: (a) superiority or equivalence (>, <, or =) of randomized rigid and flexible images; (b) erythema severity using a visual analog scale (VAS) for all randomized images; and (c) edema severity using VAS for all randomized images. Each rating was performed twice, in random order, for purposes of computing interjudge and intrajudge reliability. The results indicated that images from rigid endoscopy were of superior quality than those from flexible endoscopy. Additionally, the magnitude of severity ratings was greater for flexible versus rigid images. These findings offer confirmatory evidence that rigid endoscopy remains the preferred method for endoscopic analysis; however, flexible endoscopy is a novel, viable alternative that permits reliable visual-perceptual analysis during in vivo small animal voice research.

Previous research shows that social biases, such as pro-White racial bias, can influence a person's decisions and behaviors (Correll et al. 2007; Mekawi & Bresin, 2015). Studies also suggest that social biases may influence basic functions like visual perception (Cesario & Navarrete, 2014); however, few studies have examined the relationship between visual perceptions and threat (Cesario, Placks, Hagiwara, Navarrete, & Higgins, 2010; Todd, Thiem, & Neel, 2016). The current research aims to investigate whether implicit pro-White preference can influence basic functions like visual perception. A secondary aim of this study is to examine the role of threat in this relationship. To test, White male and female participants (N= 29) were asked to complete distance estimates to either a Black or White male experimenter. It was hypothesized that participants would judge the distance to the Black confederate as closer compared to those who estimate the distance to a White confederate. The results marginally supported the idea that participants’ distance judgements were influenced by the experimenter’s race, such that the Black experimenter was viewed as closer when compared to the White experimenter. However, results showed that implicit racial attitudes did not influence distance estimations, but explicit bias did. Fully powered follow-up studies will be conducted to further examine these hypotheses and investigate whether a type one error was present.

Down syndrome (DS) is the most common genetic cause of mental challenge in individuals and is associated with many ocular disorders. One of these anomalies which is frequently present in this population is reduced accommodation and many studies have reported this. Accommodation is the ability of the crystalline lens in the eye to focus for objects at different distances. Prescribing bifocals could potentially help in correcting the resultant inaccurate focus, although this modality of treatment is not very commonly practiced. The impact of bifocals on reading and literacy skills (academic skills) as well as visual-perceptual skills in individuals with DS has not been studied previously. The aim of this study was to investigate the impact of bifocals on the educational attainment of children and young adults with DS who have reduced accommodation and monitor their performance longitudinally. This is the first time that the impact of bifocal provision on the functional performance of children and young adults with DS has been studied. Also for the first time in children with DS, frequent measures of performance have been used to control for progression with time before and after bifocal prescription. A battery of tests comprising early literacy and visual-perceptual skills was administered before and after bifocal prescription. Accommodation and printing skills were also measured periodically. It was expected that the prescription of bifocals would help to improve near visual acuity and that the improved near acuity would result in educational achievements at school. Compliance with spectacle wear and school reports were also considered. A longitudinal observational study design was utilized with each child acting as his/her own control. Fourteen children and teenagers aged 8-18 with DS were recruited and underwent a basic optometric exam including measurement of their accommodative ability and a cycloplegic refraction. Seventy nine percent required a change in their spectacle prescription and were prescribed single vision (SV) lenses. One hundred percent had reduced accommodation both before and after new SV glasses were prescribed. Distance visual acuity did not significantly improve with SV lenses (p>0.05) but near visual acuity showed a significant improvement (p-=0.015) from 0.64±0.25 logMAR to 0.54±0.20 logMAR. A high prevalence of high refractive errors, including both hyperopia and myopia, was observed t andnear visual acuity even with a habitual correctionwas reduced compared to distance VA. A full battery of reading and visual-perceptual tests was administered with SV lenses. Thereafter the participants were followed for 6 months and monthly subtests (probes) of literacy skills and printing tasks were administered. These “probes” acted as immediate indicators of the child’s performance with his/her correction and change in performance over this time period was monitored. Over the 6 months the participants showed no noteworthy progression in their literacy skills. The group of participants performed at an age-equivalent between 3-10 years. The quality of printing formation in this population has been studied for the first time and showed no significant change over time. It was observed that some aspects of visual-perceptual and early literacy skills could be measured in all the participants. Chronological age and receptive vocabulary were significantly correlated with visual motor integration and Word Identification. Eighty five percent of the participants were prescribed bifocals with additions ranging from +1.00D to +3.50D at the 6th month after the provision of SV lenses. Post-bifocal measures of visual acuity, accommodation, visual-perceptual and early literacy skills were taken 1-2 weeks, and finally 5 months, after bifocal correction. Throughout the pre- and post-bifocal period, verbal compliance with spectacle wear was assessed through school and parental reports. The mean near logMAR VA improved with bifocals (p=0.007) compared to SV lenses. Accommodative accuracy improved with bifocals (less accommodative lag) compared to SV lenses (p=0.002) but there was no change in the accommodation exerted through the distance portion of the lens compared to SV lenses (p=0.423). There was a main effect of bifocals on sight words (p=0.013), Word Identification (p=0.047), and 2 out of 3 tests of visual perception (p<0.05). It was observed that bifocals have a positive impact on the children’s visual and school performance and this was supported by reports of improved performance in school for nine out of eleven individuals who were prescribed bifocals. The children adapted to bifocals more readily than the SV glasses, wearing them for the majority of their waking time. All the sessions of early literacy and visual-perceptual skills administered throughout the duration of the study were videotaped and were then analyzed by a naïve examiner. The time taken to perform each task was calculated and compared between the main single vision and bifocal visits. There was a significant decrease in the completion times on the test battery with bifocals for Word Identification (p=0.0015) and the Dolch sight words (p=0.048). All participants who completed the monthly probes took less time to complete the Dolch sight words (p= 0.025) and the number writing task (p=0.001) with bifocals. Similar results were not observed for the visual-perceptual tests. Performance in the monthly probes was compared before and after bifocal prescription in terms of the average raw scores and time taken. The rate of improvement in performance with bifocals was calculated by plotting the test scores against time and determing the regression lines. There was an overall significant improvement in the monthly probe scores of Word Identification (p=0.050), Dolch sight words (p=0.025) and the number test (p=0.023) with bifocals. The rate of progression in scores increased with bifocals for the Word Identification (p=0.008). Evidence of improved and faster performance with bifocals on some literacy skills was seen. It was concluded that bifocals, which result in improved near focusing, help individuals with DS to maximize their educational potential. It is suggested that more children and teenagers with DS will benefit from bifocal prescription, as they were observed to improve near visual acuity and enable better focusing for near. This thesis has provided a comprehensive analysis of the some tests of literacy, visual- perceptual and early printing skills before and after a bifocal prescription in a group of children and teenagers with Down syndrome. This is the first study to longitudinally monitor the educational impact of bifocals in a population with Down syndrome. Furthermore, the quality of printing formation in this population is a previously unstudied area and was studied longitudinally prior to and after bifocal intervention. The impact of bifocals on printing skills is also discussed. Another novel approach was that all the literacy, writing and visual-perceptual tasks sessions were videotaped to calculate the time taken to complete each task pre- and post-bifocals. This thesis is an addition to the existing literature on bifocal prescription in Down syndrome populations. From the findings in this thesis, the following recommendations are made in order to improve the standard of clinical eye care in this population. Measurement of accommodation should be considered a routine test in the clinical ocular examination for young individuals with DS, now that it is known that many of them present with accommodative deficits. When accommodation is found to be reduced, prescription of bifocals is indicated and should also become the standard of care in this population.

Down syndrome (DS) is the most common genetic cause of mental challenge in individuals and is associated with many ocular disorders. One of these anomalies which is frequently present in this population is reduced accommodation and many studies have reported this. Accommodation is the ability of the crystalline lens in the eye to focus for objects at different distances. Prescribing bifocals could potentially help in correcting the resultant inaccurate focus, although this modality of treatment is not very commonly practiced. The impact of bifocals on reading and literacy skills (academic skills) as well as visual-perceptual skills in individuals with DS has not been studied previously. The aim of this study was to investigate the impact of bifocals on the educational attainment of children and young adults with DS who have reduced accommodation and monitor their performance longitudinally. This is the first time that the impact of bifocal provision on the functional performance of children and young adults with DS has been studied. Also for the first time in children with DS, frequent measures of performance have been used to control for progression with time before and after bifocal prescription. A battery of tests comprising early literacy and visual-perceptual skills was administered before and after bifocal prescription. Accommodation and printing skills were also measured periodically. It was expected that the prescription of bifocals would help to improve near visual acuity and that the improved near acuity would result in educational achievements at school. Compliance with spectacle wear and school reports were also considered. A longitudinal observational study design was utilized with each child acting as his/her own control. Fourteen children and teenagers aged 8-18 with DS were recruited and underwent a basic optometric exam including measurement of their accommodative ability and a cycloplegic refraction. Seventy nine percent required a change in their spectacle prescription and were prescribed single vision (SV) lenses. One hundred percent had reduced accommodation both before and after new SV glasses were prescribed. Distance visual acuity did not significantly improve with SV lenses (p>0.05) but near visual acuity showed a significant improvement (p-=0.015) from 0.64±0.25 logMAR to 0.54±0.20 logMAR. A high prevalence of high refractive errors, including both hyperopia and myopia, was observed t andnear visual acuity even with a habitual correctionwas reduced compared to distance VA. A full battery of reading and visual-perceptual tests was administered with SV lenses. Thereafter the participants were followed for 6 months and monthly subtests (probes) of literacy skills and printing tasks were administered. These “probes” acted as immediate indicators of the child’s performance with his/her correction and change in performance over this time period was monitored. Over the 6 months the participants showed no noteworthy progression in their literacy skills. The group of participants performed at an age-equivalent between 3-10 years. The quality of printing formation in this population has been studied for the first time and showed no significant change over time. It was observed that some aspects of visual-perceptual and early literacy skills could be measured in all the participants. Chronological age and receptive vocabulary were significantly correlated with visual motor integration and Word Identification. Eighty five percent of the participants were prescribed bifocals with additions ranging from +1.00D to +3.50D at the 6th month after the provision of SV lenses. Post-bifocal measures of visual acuity, accommodation, visual-perceptual and early literacy skills were taken 1-2 weeks, and finally 5 months, after bifocal correction. Throughout the pre- and post-bifocal period, verbal compliance with spectacle wear was assessed through school and parental reports. The mean near logMAR VA improved with bifocals (p=0.007) compared to SV lenses. Accommodative accuracy improved with bifocals (less accommodative lag) compared to SV lenses (p=0.002) but there was no change in the accommodation exerted through the distance portion of the lens compared to SV lenses (p=0.423). There was a main effect of bifocals on sight words (p=0.013), Word Identification (p=0.047), and 2 out of 3 tests of visual perception (p<0.05). It was observed that bifocals have a positive impact on the children’s visual and school performance and this was supported by reports of improved performance in school for nine out of eleven individuals who were prescribed bifocals. The children adapted to bifocals more readily than the SV glasses, wearing them for the majority of their waking time. All the sessions of early literacy and visual-perceptual skills administered throughout the duration of the study were videotaped and were then analyzed by a naïve examiner. The time taken to perform each task was calculated and compared between the main single vision and bifocal visits. There was a significant decrease in the completion times on the test battery with bifocals for Word Identification (p=0.0015) and the Dolch sight words (p=0.048). All participants who completed the monthly probes took less time to complete the Dolch sight words (p= 0.025) and the number writing task (p=0.001) with bifocals. Similar results were not observed for the visual-perceptual tests. Performance in the monthly probes was compared before and after bifocal prescription in terms of the average raw scores and time taken. The rate of improvement in performance with bifocals was calculated by plotting the test scores against time and determing the regression lines. There was an overall significant improvement in the monthly probe scores of Word Identification (p=0.050), Dolch sight words (p=0.025) and the number test (p=0.023) with bifocals. The rate of progression in scores increased with bifocals for the Word Identification (p=0.008). Evidence of improved and faster performance with bifocals on some literacy skills was seen. It was concluded that bifocals, which result in improved near focusing, help individuals with DS to maximize their educational potential. It is suggested that more children and teenagers with DS will benefit from bifocal prescription, as they were observed to improve near visual acuity and enable better focusing for near. This thesis has provided a comprehensive analysis of the some tests of literacy, visual- perceptual and early printing skills before and after a bifocal prescription in a group of children and teenagers with Down syndrome. This is the first study to longitudinally monitor the educational impact of bifocals in a population with Down syndrome. Furthermore, the quality of printing formation in this population is a previously unstudied area and was studied longitudinally prior to and after bifocal intervention. The impact of bifocals on printing skills is also discussed. Another novel approach was that all the literacy, writing and visual-perceptual tasks sessions were videotaped to calculate the time taken to complete each task pre- and post-bifocals. This thesis is an addition to the existing literature on bifocal prescription in Down syndrome populations. From the findings in this thesis, the following recommendations are made in order to improve the standard of clinical eye care in this population. Measurement of accommodation should be considered a routine test in the clinical ocular examination for young individuals with DS, now that it is known that many of them present with accommodative deficits. When accommodation is found to be reduced, prescription of bifocals is indicated and should also become the standard of care in this population.

abstract: Magnocellular-Dorsal pathway’s function had been related to reading ability, and visual perceptual learning can effectively increase the function of this neural pathway. Previous researches training people with a traditional dot motion paradigm and an integrated visual perceptual training “video game” called Ultimeyes pro, all showed improvement with regard to people’s reading performance. This research used 2 paradigms in 2 groups in order to compare the 2 paradigms’ effect on improving people’s reading ability. We also measured participants’ critical flicker fusion threshold (CFFT), which is related to word decoding ability. The result did not show significant improvement of reading performance in each group, but overall the reading speed improved significantly. The result for CFFT in each group only showed significant improvement among people who trained with Ultimeyes pro. This result supports that the beneficial effect of visual perceptual learning training on people’s reading ability, and it suggests that Ultimeyes pro is more efficient than the traditional dot motion paradigm, and might have more application value. / Dissertation/Thesis / Masters Thesis Psychology 2015

The purpose of this thesis is to examine the effects of inhaled corticosteroid drugs (ICs) on the voice due to their frequent use in treating an increasing prevalence of asthma disorders. As part of a larger five-year study, the focus of this thesis is specifically on whether 8 weeks of in vivo exposure to ICs will cause changes in the sustained subglottal pressure, sustained airflow, and visual-perceptual ratings of edema and erythema in excised rabbit larynges. Researchers administered either ICs or a control nebulized isotonic saline solution to 22 rabbits in vivo, sacrificed them, and harvested their larynges for benchtop research. While ensuring proper tissue preservation, researchers then finely dissected the larynges to expose the true vocal folds and run phonation trials. Dependent variables included continuous acoustic signals (Hz), subglottal pressure (cm H2O), and airflow (L/min) data for 15 phonation trials per rabbit larynx. Researchers also collected still image photographs at this time and subsequently normalized them for use in the visual-perceptual portion of this thesis. For visual-perceptual ratings, raters used a 0-3 equal appearing interval scale to rate aspects of edema and erythema on left and right vocal fold and arytenoid tissues. Results indicate that, when compared to control larynges exposed to nebulized isotonic saline, experimental larynges treated with ICs require significantly higher subglottal pressure to maintain phonation, p < .05. Mean sustained phonation for experimental larynges is 11.24 cm H2O compared to 8.92 cm H2O for that of control larynges. Phonation trials for experimental larynges have significantly higher sustained airflow with a mean of 0.09 L/min compared to 0.07 L/min for that of control larynges, p < .05. Surprisingly, experimental larynges have higher average fundamental frequencies with less variability (mean: 519 Hz, standard deviation: 66 Hz) than that of control larynges (mean: 446 Hz, standard deviation: 130 Hz). On visual-perceptual ratings, experimental larynges have significantly higher severity ratings on all eight items rated, p < .0001 - p = .0305. Based on these results, it is concluded that ICs cause significant damage to rabbit vocal folds, as evidenced by higher sustained pressure, higher airflow, and higher severity ratings for experimental versus control larynges. The dependent variables in this thesis are novel in benchtop model research and demonstrate a unique perspective on this research question. Thus, this thesis informs future phonation, benchtop, and visual-perceptual research.

Identifying targets in cluttered scenes is critical for our interactions in complex environments. Our visual system is challenged to both detect elusive targets that we may want to avoid or chase and discriminate between targets that are highly similar. These tasks require our visual system to become an expert at detecting distinctive features that help us differentiate between indistinguishable targets. As the human brain is trained on this type of visual tasks, we observe changes in its function that correspond to improved performance. We use functional brain imaging, to measure learning-dependent modulations of brain activation and investigate the processes that mediate functional brain plasticity. I propose that dissociable brain mechanisms are engaged when detecting targets in clutter vs. discriminating between highly similar targets: for the former, background clutter needs to be suppressed for the target to be recognised, whereas for the latter, neurons are tuned to respond to fine differences. Although GABAergic inhibition is known to suppress redundant neuronal populations and tune neuronal representations, its role in visual learning remains largely unexplored. Here, I propose that GABAergic inhibition plays an important role in visual plasticity through training on these tasks. The purpose of my PhD is to investigate the inhibitory mechanisms that mediate visual perceptual learning; in particular, learning to detect patterns in visual clutter and discriminate between highly similar patterns. I show that BOLD signals as measured by functional Magnetic Resonance Imaging (fMRI) do not differentiate between the two proposed mechanisms. In contrast, Magnetic Resonance Spectroscopy (MRS) provides strong evidence for the distinct involvement of GABAergic inhibition in visual plasticity. Further, my findings show GABA changes during the time-course of learning providing evidence for a distinct role of GABA in learning-dependent plasticity across different brain regions involved in visual learning. Finally, I test the causal link between inhibitory contributions and visual plasticity using a brain stimulation intervention that perturbs the excitation-inhibition balance in the visual cortex and facilitates learning.

The aim of this field study was to investigate the relationship between visual perceptual processes and drawing ability in Year 7 students in the Australian Capital Territory. A random sample of five classes from five High Schools, consisting of 113 year 7 students, was tested for their ability in representational and memory drawing, and a sample of good drawers was chosen by a panel of five Independent judges. The drawing ability of the "Good" Drawers Sample was tested by means of Field's Visual Information Transformation Test (VIT), and the visual perceptual processes were tested using MacGregor's Perceptual Index.(MPI) A statistical analysis of the ranked scores was made using the Kruskal Wallis Analysis of Variance, the Spearman Rho rank order correlation, and the Mann Whitney U Test.

Summaries in Afrikaans and English / Text in Afrikaans / Die waarde van visueel-perseptuele skoling of terapie vir visueel-perseptueel gestremde leerlinge as 'n subgroep van leergestremdheid, is reeds vir dekades 'n omstrede aangeleentheid. Hierdie omstredenheid is ondersoek aan die hand van sewe internasionaal erkende psigometriese toetse. Die interne konsekwentheidskoeffisiente van hierdie toetse het vir die huidige studie van 0,62 tot 0,95 gestrek. 'n Faktorontleding van die toetsinterkorrelasies het 'n gemeenskaplike faktor blootgele. Ses toetse was primer visueel-perseptueel, en Goodenough <1926> se skaal is vir die bepaling van intelligensie gebruik. Bykomend hiertoe, is leerlinge se prestasies in hul eerste taal, wiskunde en skrif gebruik om die effek van terapie te bepaal. Proefpersone is as visueel-perseptueel gestremd gediagnoseer deur 'n opvoedkundige sielkundige en 'n visuele skolingsentrum in Pretoria, waar eksper imentele leerlinge terapie ontvang het. Hierdie diagnoses is deur die Test for Visual Analysis Skills wat beduidend tussen normale en visueelperseptueel gestremdes onderskei, bevestig. Die toets se geldigheid vir Suid-Afrikaanse omstandighede is in 'n voorstudie bepaal. Honderd en ses, ses- tot negejarige proefpersone (82 seuns en 24 dogters>, van normale intelligensie, gesigskerpte en gehoor, is betrek. Drie en vyftig het die eksperimentele groep gevorm wat onderverdeel is in 32 wat terapie voltooi het, en 21 wat nie het nie. Hierdie leerlinge is individueel afgepaar met kontroleleerlinge van dieselfde geslag, ouderdom, huistaal, sosio-ekonomiese status en skoolstanderd. Eksperimentele leerlinge het visuele terapie in n breer groepsverband vir een uur per week ontvang. Terapieperiodes het van 4 tot 15 maande gewissel. Die eksperimentele ontwerp was 'n voortoets-natoets-tweegroepontwerp. t-Toetse vir afhanklike (afgepaarde) groepe is uitgevoer op die verskille tussen voor- en natoetstellings, asook tussen die eksperimentele en kontrolegroepe. Geeneen van die primer visueel-oerseptuele meettegnieke het beduidende resultate opgelewer nie. Dit is aanduidend van die ondoeltreffendheid van visueel-perseptuele terapie om die tekorte waarop dit gemik is, reg te stel. Die waarde van visueel-perseptueie terapie is inteendeel beperk tot 'n oorhoofse verbetering in konseptualisering en intellektuele ryping by die groep wat terapie voltooi het. Skrif was die enigste vak wat by dieselfde groep beduidend verbeter het. Hierdie resultaat is egter twyfelagtig vanwee beoordelingstekorte. / The value of visual perceptual training or therapy, to visually perceptually impaired pupils as a subgroup of the learning disabled, has been a controversy far decades. This controversy was investigated by means of seven internationally recognised psychometric tests. The internal consistency coefficients of these tests for the present study ranged from 0,62 to 0,95. A factor analysis of test intercorrelations revealed a common factor. Six tests were primarily visual perceptual, whilst the Goodenough (1926) scale determined intelligence. Additionally, pupils' performance in their first language, mathematics and writing, was used to assess the therapeutic effect. Subjects were diagnosed as visually perceptually impaired by an educational psychologist and a visual training centre in Pretoria where experimental pupils received therapy. These diagnoses were confirmed by the Test for Visual Analysis Skills, which significantly differentiates between the normal and visually perceptually impaired. This test's validity for South African circumstances was determined in a prestudy. One hundred and six, six to nine year old subjects <82 boys and 24 girls>, of normal intelligence, visual acuity and hearing, were involved. Fifty three formed the experimental group which was subdivided in 32 who completed therapy, and 21 who did not. These pupils were individualiy matched with controls of similar sex, age, home language, socio economic status and school standard. Experimental pupils received visual therapy within a broader group context for one hour per week. Therapy periods fluctuated between 4 and 15 months. The experimental design was a pretest-posttest two group design. t-Tests for dependant <matched) groups were conducted on the differences between pre and oosttest scores, as well as between the experimental and control groups. None of the primarily visual perceptual tests revealed significant results. This signifies the inefficiency of visual perceptual therapy to rectify the deficits at which it is directed. The value of visual perceptual therapy is, on the contrary, restricted to an overall improvement in conceptualization and intellectual maturation within the group which completed therapy. Writing was the only subject which improved significantly within the same group. However, this result is dubious, due to evaluation deficits. / Psychology / D.Litt. et Phil. (Psychology)

Summaries in Afrikaans and English / Text in Afrikaans / Die waarde van visueel-perseptuele skoling of terapie vir visueel-perseptueel gestremde leerlinge as 'n subgroep van leergestremdheid, is reeds vir dekades 'n omstrede aangeleentheid. Hierdie omstredenheid is ondersoek aan die hand van sewe internasionaal erkende psigometriese toetse. Die interne konsekwentheidskoeffisiente van hierdie toetse het vir die huidige studie van 0,62 tot 0,95 gestrek. 'n Faktorontleding van die toetsinterkorrelasies het 'n gemeenskaplike faktor blootgele. Ses toetse was primer visueel-perseptueel, en Goodenough <1926> se skaal is vir die bepaling van intelligensie gebruik. Bykomend hiertoe, is leerlinge se prestasies in hul eerste taal, wiskunde en skrif gebruik om die effek van terapie te bepaal. Proefpersone is as visueel-perseptueel gestremd gediagnoseer deur 'n opvoedkundige sielkundige en 'n visuele skolingsentrum in Pretoria, waar eksper imentele leerlinge terapie ontvang het. Hierdie diagnoses is deur die Test for Visual Analysis Skills wat beduidend tussen normale en visueelperseptueel gestremdes onderskei, bevestig. Die toets se geldigheid vir Suid-Afrikaanse omstandighede is in 'n voorstudie bepaal. Honderd en ses, ses- tot negejarige proefpersone (82 seuns en 24 dogters>, van normale intelligensie, gesigskerpte en gehoor, is betrek. Drie en vyftig het die eksperimentele groep gevorm wat onderverdeel is in 32 wat terapie voltooi het, en 21 wat nie het nie. Hierdie leerlinge is individueel afgepaar met kontroleleerlinge van dieselfde geslag, ouderdom, huistaal, sosio-ekonomiese status en skoolstanderd. Eksperimentele leerlinge het visuele terapie in n breer groepsverband vir een uur per week ontvang. Terapieperiodes het van 4 tot 15 maande gewissel. Die eksperimentele ontwerp was 'n voortoets-natoets-tweegroepontwerp. t-Toetse vir afhanklike (afgepaarde) groepe is uitgevoer op die verskille tussen voor- en natoetstellings, asook tussen die eksperimentele en kontrolegroepe. Geeneen van die primer visueel-oerseptuele meettegnieke het beduidende resultate opgelewer nie. Dit is aanduidend van die ondoeltreffendheid van visueel-perseptuele terapie om die tekorte waarop dit gemik is, reg te stel. Die waarde van visueel-perseptueie terapie is inteendeel beperk tot 'n oorhoofse verbetering in konseptualisering en intellektuele ryping by die groep wat terapie voltooi het. Skrif was die enigste vak wat by dieselfde groep beduidend verbeter het. Hierdie resultaat is egter twyfelagtig vanwee beoordelingstekorte. / The value of visual perceptual training or therapy, to visually perceptually impaired pupils as a subgroup of the learning disabled, has been a controversy far decades. This controversy was investigated by means of seven internationally recognised psychometric tests. The internal consistency coefficients of these tests for the present study ranged from 0,62 to 0,95. A factor analysis of test intercorrelations revealed a common factor. Six tests were primarily visual perceptual, whilst the Goodenough (1926) scale determined intelligence. Additionally, pupils' performance in their first language, mathematics and writing, was used to assess the therapeutic effect. Subjects were diagnosed as visually perceptually impaired by an educational psychologist and a visual training centre in Pretoria where experimental pupils received therapy. These diagnoses were confirmed by the Test for Visual Analysis Skills, which significantly differentiates between the normal and visually perceptually impaired. This test's validity for South African circumstances was determined in a prestudy. One hundred and six, six to nine year old subjects <82 boys and 24 girls>, of normal intelligence, visual acuity and hearing, were involved. Fifty three formed the experimental group which was subdivided in 32 who completed therapy, and 21 who did not. These pupils were individualiy matched with controls of similar sex, age, home language, socio economic status and school standard. Experimental pupils received visual therapy within a broader group context for one hour per week. Therapy periods fluctuated between 4 and 15 months. The experimental design was a pretest-posttest two group design. t-Tests for dependant <matched) groups were conducted on the differences between pre and oosttest scores, as well as between the experimental and control groups. None of the primarily visual perceptual tests revealed significant results. This signifies the inefficiency of visual perceptual therapy to rectify the deficits at which it is directed. The value of visual perceptual therapy is, on the contrary, restricted to an overall improvement in conceptualization and intellectual maturation within the group which completed therapy. Writing was the only subject which improved significantly within the same group. However, this result is dubious, due to evaluation deficits. / Psychology / D.Litt. et Phil. (Psychology)